God is no longer adding to His book of the law, the bible. This is after any manner of brining new prophecy. We have all the laws necessary for knowing him perfect or completely, nothing missing by which we could know Him more adequately
He warns of those who would add ,like Mohammed, the false prophet Charles Mansion, Jim Jones or Joseph Smith. Any person who said; thus saying the Lord, after the book of Revelation was complete sealing up the posiillty of another new prophecy after any manner.
Unbelievers like believer are still susceptible to vision as lying signs and wonders. Satan will be brining them trying to seduce men to add to His word right up till the last day.
Every time a person hears of a what some call out of the body experience, which is lying spirit brining illusions in, we can know it the father of lies.
When the Son of Man Jesus received a lying vision in Mathew 4, Three times Jesus said.. as it is written with the word it pointing to the true source of faith that comes from hearing God. The devil did flee.